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<p>Reports shadowing built-in names, such as <code>len</code> or <code>list</code>.</p>
<p><b>Example:</b></p>
<pre><code>
def len(a, b, c):
    d = a + b + c
    return d
</code></pre>
<p>In this code fragment, the <code>len</code> built-in name is used. The IDE offers to
  apply the Rename refactoring as a fix.</p>
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